Is legitimacy killing street art?

The Guardian's art correspondent Jonathan Jones argues that mainstream acceptance is killing street art; how what used to be an outlaw pursuit, charged with an edgy, subversive frisson, is now thoroughly commodified, exhibited in galleries, flogged en masse to tourists and posed alongside by centre-right politicians, fatally eroding what underground credibility it once had:

Visitors to London buy Banksy prints on canvas from street stalls, while in Tripoli photographers latch on to any bloke with a spray can near any wall that's still standing. Graffiti and street art have become instant – and slightly lazy – icons of everything our culture lauds, from youth to rebellion to making a fast buck from art.

Maybe there was a time when painting a wittily satirical or cheekily rude picture or comment on a wall was genuinely disruptive and shocking. That time is gone. Councils still do their bit to keep street art alive by occasionally obliterating it, and so confirming that it has edge. But basically it has been absorbed so deep into the mainstream that old folk who once railed at graffiti in their town are now more likely to have a Banksy book on their shelves than a collection of Giles cartoons.

He has a point about the mainstreaming and commodification of once transgressive phenomena (recently we have witnessed the confirmation of punk's position as a safe and cozy part of Britain's heritage by the National Trust releasing a punk compilation album), and the fact that there is a lot of street art which, when one puts aside its illegality and unconventional locations, is quite mediocre. Though the final stage of this process of commodification seems less than apocalyptic: a culture in which street art becomes a sort of accepted folk art, sometimes critical or confrontational, occasionally brilliant, more often mediocre, and very occasionally leading to wealth and fame, though generally practiced by small-time artists, and tolerated by society as part of the local culture and the broader conversation. Which, to me, looks healthier than a society of zero-tolerance policies, where the means of street-level communication belong exclusively to corporate advertisers.